Bifurcation graft deployment catheter

ABSTRACT

A deployment catheter for deploying a tubular endoluminal vascular prosthesis includes a proximal tubular section and a distal tubular section which are axially movable in opposite directions to deploy the prosthesis. A central core extends throughout the proximal tubular section and into the distal tubular section. In one embodiment, a reinforcing structure is carried by the central core, spanning the junction between the proximal tubular section and distal tubular section. In another embodiment, the proximal tubular section and/or distal tubular section are rotationally linked to the central-core.

This is a continuation-in-part of Ser. No. 09/251,363, filed Feb. 17,1999, now U.S. Pat. No. 6,197,049, which is a continuation-in-part ofSer. No. 09/210,280, filed Dec. 11, 1998, now U.S. Pat. No. 6,187,036,the disclosures of each of which are incorporated in their entiretiesherein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to endoluminal vascular prosthesisdeployment catheters, and in particular, to a deployment catheter forself-expanding straight segment or bifurcated prostheses for use in thetreatment of abdominal aortic aneurysms.

An abdominal aortic aneurysm is a sac caused by an abnormal dilation ofthe wall of the aorta, a major artery of the body, as it passes throughthe abdomen. The abdomen is that portion of the body which lies betweenthe thorax and the pelvis. It contains a cavity, known as the abdominalcavity, separated by the diaphragm from the thoracic cavity and linedwith a serous membrane, the peritoneum. The aorta is the main trunk, orartery, from which the systemic arterial system proceeds. It arises fromthe left ventricle of the heart, passes upward, bends over and passesdown through the thorax and through the abdomen to about the level ofthe fourth lumbar vertebra, where it divides into the two common iliacarteries.

The aneurysm usually arises in the infrarenal portion of the diseasedaorta, for example, below the kidneys. When left untreated, the aneurysmmay eventually cause rupture of the sac with ensuing fatal hemorrhagingin a very short time. High mortality associated with the rupture ledinitially to transabdominal surgical repair of abdominal aorticaneurysms. Surgery involving the abdominal wall, however, is a majorundertaking with associated high risks. There is considerable mortalityand morbidity associated with this magnitude of surgical intervention,which in essence involves replacing the diseased and aneurysmal segmentof blood vessel with a prosthetic device which typically is a synthetictube, or graft, usually fabricated of Polyester, Urethane, DACRON®,TEFLON®, or other suitable material.

To perform the surgical procedure requires exposure of the aorta throughan abdominal incision which can extend from the rib cage to the pubis.The aorta must be closed both above and below the aneurysm, so that theaneurysm can then be opened and the thrombus, or blood clot, andarteriosclerotic debris removed. Small arterial branches from the backwall of the aorta are tied off. The DACRON® tube, or graft, ofapproximately the same size of the normal aorta is sutured in place,thereby replacing the aneurysm. Blood flow is then reestablished throughthe graft. It is necessary to move the intestines in order to get to theback wall of the abdomen prior to clamping off the aorta.

If the surgery is performed prior to rupturing of the abdominal aorticaneurysm, the survival rate of treated patients is markedly higher thanif the surgery is performed after the aneurysm ruptures, although themortality rate is still quite high. If the surgery is performed prior tothe aneurysm rupturing, the mortality rate is typically slightly lessthan 10%. Conventional surgery performed after the rupture of theaneurysm is significantly higher, one study reporting a mortality rateof 66.5%. Although abdominal aortic aneurysms can be detected fromroutine examinations, the patient does not experience any pain from thecondition. Thus, if the patient is not receiving routine examinations,it is possible that the aneurysm will progress to the rupture stage,wherein the mortality rates are significantly higher.

Disadvantages associated with the conventional, prior art surgery, inaddition to the high mortality rate include the extended recovery periodassociated with such surgery; difficulties in suturing the graft, ortube, to the aorta; the loss of the existing aorta wall and thrombosisto support and reinforce the graft; the unsuitability of the surgery formany patients having abdominal aortic aneurysms; and the problemsassociated with performing the surgery on an emergency basis after theaneurysm has ruptured. A patient can expect to spend from one to twoweeks in the hospital after the surgery, a major portion of which isspent in the intensive care unit, and a convalescence period at homefrom two to three months, particularly if the patient has otherillnesses such as heart, lung, liver, and/or kidney disease, in whichcase the hospital stay is also lengthened. The graft must be secured, orsutured, to the remaining portion of the aorta, which may be difficultto perform because of the thrombosis present on the remaining portion ofthe aorta. Moreover, the remaining portion of the aorta wall isfrequently friable, or easily crumbled.

Since many patients having abdominal aortic aneurysms have other chronicillnesses, such as heart, lung, liver, and/or kidney disease, coupledwith the fact that many of these patients are older, the average agebeing approximately 67 years old, these patients are not idealcandidates for such major surgery.

More recently, a significantly less invasive clinical approach toaneurysm repair, known as endovascular grafting, has been developed.Parodi, et al. provide one of the first clinical descriptions of thistherapy. Parodi, J. C., et al., “Transfemoral Intraluminal GraftImplantation for Abdominal Aortic Aneurysms,” 5 Annals of VascularSurgery 491 (1991). Endovascular grafting involves the transluminalplacement of a prosthetic arterial graft within the lumen of the artery.

In general, transluminally implantable prostheses adapted for use in theabdominal aorta comprise a tubular wire cage surrounded by a tubularPTFE or Dacron sleeve. Both balloon expandable and self expandablesupport structures have been proposed. Endovascular grafts adapted totreat both straight segment and bifurcation aneurysms have also beenproposed.

Notwithstanding the foregoing, there remains a need for a structurallysimple, easily deployable transluminally implantable endovascularprosthesis, with a support structure adaptable to span either a straightor bifurcated abdominal aortic aneurysm. Preferably, the tubularprosthesis can be self expanded at the site to treat the abdominalaortic aneurysm, and exhibits flexibility to accommodate nonlinearanatomies and normal anatomical movement.

SUMMARY OF THE INVENTION

There is provided in accordance with one aspect of the presentinvention, an endoluminal graft deployment catheter. The cathetercomprises a proximal outer tube section, having a proximal end and adistal end, and an intermediate tube extending through the proximal tubesection and beyond the distal end. A central core extends through theintermediate tube, and a cap is attached to the central core. Thecentral core is rotationally linked to the intermediate tube.

Preferably, the intermediate tube is rotationally linked to the outertube. The cap is axially movable between a first position in which itcontacts the outer tube and a second position in which it is spaceddistally apart from the outer tube, such as to deploy an entrappedprosthesis.

The central core preferably comprises a flexible tube. In oneembodiment, the tube comprises a polymeric braid. One suitable polymeris polyimide.

In accordance with a further aspect of the present invention, thecentral core further comprises a reinforcing element which, overlaps thepoint of contact between the cap and the outer tube. In one embodiment,the reinforcing element comprises a tubular structure carried by theflexible central core.

In accordance with a further aspect of the present invention, there isprovided an endoluminal graft deployment catheter. The cathetercomprises an elongate flexible body, having a proximal end and a distalend. A proximal outer tube section has a proximal end and a distal end,and a distal outer tube section has a proximal end and a distal end. Theproximal outer tube section is rotationally linked to the distal outertube section, and a central core extends through the proximal end distalouter tube sections. The proximal and distal tube sections define aprosthesis cavity therein for carrying a prosthesis, and axialseparation of the proximal tube section from the distal tube sectionopens the cavity to release the prosthesis.

In one embodiment, each of the proximal tube section and distal tubesection is rotationally linked to the central core. At least one of theproximal tube section and distal tube section is axially movable betweena first position in which the cavity is closed and a second position inwhich the cavity is open. The proximal tube section and distal tubesection thus form a junction when in the first position, and thecatheter preferably further comprises a reinforcing element which spansthe junction. In one embodiment, the reinforcing element comprises atube for surrounding the central core.

Further features and advantages of the present invention will becomeapparent to those of ordinary skill in the art in view of the disclosureherein, when considered together with the attached drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a bifurcated vascular prosthesisin accordance with the present invention, positioned at the bifurcationbetween the abdominal aorta and the right and left common iliacarteries.

FIG. 2 is a cross-sectional view of the implanted graft taken along thelines 2—2 of FIG. 1.

FIG. 3 is an exploded view of the bifurcated vascular prosthesis inaccordance with the present invention, showing a two-part selfexpandable wire support structure separated from an outer tubularsleeve.

FIG. 4 is a plan view of formed wire useful for rolling about an axisinto an aortic trunk segment and a first iliac branch segment supportstructure in accordance with the present invention.

FIG. 5 is a schematic representation of another embodiment of the wiresupport structure for the bifurcated vascular prosthesis of the presentinvention, showing a main body support structure and separate branchsupport structures.

FIG. 6 is a schematic representation of the three-part wire supportstructure as in FIG. 5, illustrating the sliding articulation betweenthe branch supports and the main body support.

FIG. 7 is a plan view of formed wire useful for rolling about an axis toform a branch support structure in accordance with the three-partsupport embodiment of the present invention shown in FIG. 5.

FIGS. 8A, 8B and 8C are enlargements of the apexes delineated by linesA, B and C, respectively, in FIG. 7.

FIG. 9 is side elevational cross-section of a bifurcation graft deliverycatheter in accordance with the present invention.

FIG. 9A is a cross-section taken along line 9A—9A of FIG. 9.

FIG. 9B is a cross-section taken along line 9B—9B of FIG. 9.

FIG. 10 is an enlargement of the portion delineated by the line 10—10 inFIG. 9.

FIG. 11 is a cross-section taken along the line 11—11 in FIG. 10.

FIG. 12 is a cross-section taken along the line 12—12 in FIG. 10.

FIG. 13 is a fragmentary side elevational view of an enhancedflexibility embodiment of the present invention.

FIG. 14 is a enlarged detail view taken along the line 14—14 in FIG. 13.

FIG. 15 is a schematic representation of a bifurcated graft deploymentcatheter of the present invention, positioned within the ipsilateraliliac and the aorta, with the contralateral guidewire positioned withinthe contralateral iliac.

FIG. 16 is a schematic representation as in FIG. 15, with the outersheath proximally retracted and the compressed iliac branches of thegraft moving into position within the iliac arteries.

FIG. 17 is a schematic representation as in FIG. 16, with the compressediliac branches of the graft within the iliac arteries, and the mainaortic trunk of the graft deployed within the aorta.

FIG. 18 is a schematic representation as in FIG. 17, with thecontralateral iliac branch of the graft deployed.

FIG. 19 is a schematic representation as in FIG. 18, followingdeployment of the ipsilateral branch of the graft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, there is disclosed a schematic representation ofthe abdominal part of the aorta and its principal branches. Inparticular, the abdominal aorta 30 is characterized by a right renalartery 32 and left renal artery 34. The large terminal branches of theaorta are the right and left common iliac arteries 36 and 38. Additionalvessels (e.g., second lumbar, testicular, inferior mesenteric, middlesacral) have been omitted for simplification.

An expanded bifurcated endoluminal vascular prosthesis 102, inaccordance with one aspect of the present invention, is illustratedspanning aneurysms 103, 104 and 105. Although certain prosthesisconfigurations are disclosed herein, these are only examples ofprostheses which are deployable using the deployment catheter of thepresent invention. The deployment catheter may be used to deployessentially any self expandable bifurcated or straight segmentprosthesis, as will be apparent to those of skill in the art in view ofthe disclosure herein.

The endoluminal vascular prosthesis 102 includes a polymeric sleeve 106and a tubular wire support 107, illustrated in situ in FIG. 1. Thesleeve 106 and wire support 107 are more readily visualized in theexploded view shown in FIG. 3. The endoluminal prosthesis 102illustrated and described herein depicts an embodiment in which thepolymeric sleeve 106 is situated concentrically outside of the tubularwire support 107. However, other embodiments may include a sleevesituated instead concentrically inside the wire support or on both ofthe inside and the outside of the wire support. Alternatively, the wiresupport may be embedded within a polymeric matrix or layer which makesup the sleeve. Regardless of whether the sleeve 106 is inside or outsidethe wire support 107, the sleeve may be attached to the wire support byany of a variety of means, as has been previously discussed.

The tubular wire support 107 comprises a primary component 108 fortraversing the aorta and a first iliac, and a branch component 109 forextending into the second iliac. The primary component 108 may be formedfrom a continuous single length of wire, throughout both the aorta trunkportion and the iliac branch portion. See FIGS. 3 and 4. Alternatively,each iliac branch component can be formed separately from the aortatrunk portion. Construction of the graft from a three part cageconveniently facilitates the use of different gauge wire in thedifferent components (e.g. 0.014″ diameter main trunk and 0.012″diameter branch components).

The wire support 107 is preferably formed in a plurality of discretesegments, connected together and oriented about a common axis. In FIG.4, Section A corresponds to the aorta trunk portion of the primarycomponent 108, and includes segments 1-5. Segments 6-8 (Section B)correspond to the iliac branch portion of the primary component 108.

In general, each of the components of the tubular wire support 107 canbe varied considerably in diameter, length, and expansion coefficient,depending upon the intended application. For implantation within atypical adult, the aorta trunk portion (section A) of primary component108 will have a length within the range of from about 5 cm to about 12cm, and, typically within the range of from about 9 cm to about 10 cm.The unconstrained outside expanded diameter of the section A portion ofthe primary component 108 will typically be within the range of fromabout 20 mm to about 40 mm. The unconstrained expanded outside diameterof the section A portion of primary component 108 can be constant orsubstantially constant throughout the length of section A, or can betapered from a relatively larger diameter at the proximal end to arelatively smaller diameter at the bifurcation. In general, the diameterof the distal end of section A will be on the order of no more thanabout 95% and, preferably, no more than about 85% of the diameter of theproximal end of section A.

The right and left iliac portions, corresponding to section B on primarycomponent 108 and section C will typically be bilaterally symmetrical.Section C length will generally be within the range of from about 1 cmto about 5 cm, and section C diameter will typically be within the rangeof from about 10 mm to about 20 mm.

Referring to FIG. 3, the wire cage 107 is dividable into a proximal zone110, a central zone 111 and a distal zone 112. In addition, the wirecage 107 can have a transitional tapered and or stepped diameter withina given zone. Further details of the bifurcated and straight segmentgrafts in accordance with the present invention are disclosed incopending U.S. patent application Ser. No. 09/251,363 filed Feb. 17,1999 and entitled Articulated Bifurcation Graft, the disclosure of whichis incorporated in its entirety herein by reference.

Referring to FIG. 4, there is illustrated a plan view of the singleformed wire used for rolling about a longitudinal axis to produce aprimary segment 108 having a five segment aorta section and a threesegment iliac section. The formed wire exhibits distinct segments, eachcorresponding to an individual tubular segment in the tubular support.Additional details of the wire cage layout and construction can be foundin copending U.S. patent application Ser. No. 09/034,689 entitledEndoluminal Vascular Prosthesis, filed Mar. 4, 1998, the disclosure ofwhich is incorporated in its entirety herein by reference.

Each segment has a repeating pattern of proximal bends 60 connected tocorresponding distal bends 62 by wall sections 64 which extend in agenerally zig-zag configuration when the segment is radially expanded.Each segment is connected to the adjacent segment through a connector66, and one or more links 70 (see FIG. 6). The connector 66 in theillustrated embodiment comprises two wall sections 64 which connect aproximal bend 60 on a first segment with a distal bend 62 on a second,adjacent segment. The connector 66 may additionally be provided with aconnector bend 68, which may be used to impart increased radial strengthto the graft and/or provide a tie site for a circumferentially extendingsuture.

In the illustrated embodiment, section A is intended for deploymentwithin the aorta whereas section B is intended to be deployed within afirst iliac. Thus, section B will preferably have a smaller expandeddiameter than section A. This may be accomplished by providing fewerproximal and distal bends 60, 62 per segment in section B or in othermanners as will be apparent to those of skill in the art in view of thedisclosure herein. In the illustrated embodiment, section B has onefewer proximal bend 60 per segment than does each segment in section A.This facilitates wrapping of the wire into a tubular prosthesis cagesuch as that illustrated in FIG. 3, so that the iliac branch has asmaller diameter than the aorta branch. At the bifurcation, an openingremains for connection of the second iliac branch. The second branch ispreferably formed from a section of wire in accordance with the generalprinciples discussed above, and in a manner that produces a similarlydimensioned wire cage as that produced by section B. The second iliacbranch (section C) may be attached at the bifurcation to section Aand/or section B in any of a variety of manners, to provide a securejunction therebetween. In one embodiment, one or two of the proximalbends 60 on section C will be secured to the corresponding distal bends62 on the distal most segment of section A. Attachment may beaccomplished such as through the use of a circumferentially threadedsuture, through links 70 as has been discussed previously, throughsoldering or other attachment means. The attachment means will beinfluenced by the desired flexibility of the graft at the bifurcation,which will in turn be influenced by the method of deployment of thevascular graft as will be apparent to those of skill in the art in viewof the disclosure herein.

Referring to FIG. 5, there is disclosed an exploded schematicrepresentation of a hinged or articulated variation in the tubular wiresupport structure for a bifurcated graft in accordance with presentinvention. The tubular wire support comprises a main body, or aortictrunk portion 200 and right 202 and left 204 iliac branch portions.Right and left designations correspond to the anatomic designations ofright and left common iliac arteries. The proximal end 206 of the aortictrunk portion 200 has apexes 211-216 adapted for connection with thecomplementary apexes on the distal ends 208 and 210 of the right 202 andleft 204 iliac branch portions, respectively. Complementary pairing ofapexes is indicated by the shared numbers, wherein the right branchportion apexes are designated by (R) and the left branch portion apexesare designated by (L). Each of the portions may be formed from acontinuous single length of wire. See FIG. 7.

Referring to FIG. 6, the assembled articulated wire support structure isshown. The central or medial apex 213 in the foreground (anterior) ofthe aortic trunk portion 200 is linked with 213(R) on the right iliacportion 202 and 213(L) on the left iliac portion 204. Similarly, thecentral apex 214 in the background (posterior) is linked with 214(R) onthe right iliac portion 202 and 214(L) on the left iliac portion 204.Each of these linkages has two iliac apexes joined with one aorticbranch apex. The medial most apexes 218 (R) and (L) of the iliac branchportions 202 and 204 are linked together, without direct connection withthe aortic truck portion 200.

The medial apexes 213 and 214 function as pivot points about which theright and left iliac branches 202, 204 can pivot to accommodate uniqueanatomies. Although the right and left iliac branches 202, 204 areillustrated at an angle of about 45° to each other, they are articulablethrough at least an angle of about 90° and preferably at least about120°. The illustrated embodiment allows articulation through about 180°while maintaining patency of the central lumen. To further improvepatency at high iliac angles, the apexes 213 and 214 can be displacedproximally from the transverse plane which roughly contains apexes 211,212, 215 and 216 by a minor adjustment to the fixture about which thewire is formed. Advancing the pivot point proximally relative to thelateral apexes (e.g., 211, 216) opens the unbiased angle between theiliac branches 202 and 204.

In the illustrated embodiment, the pivot point is formed by a moveablelink between an eye on apex 213 and two apexes 213R and 213L foldedtherethrough. To accommodate the two iliac apexes 213R and 213L, thediameter of the eye at apex 213 may be slightly larger than the diameterof the eye on other apexes throughout the graft. Thus, for example, thediameter of the eye at apex 213 in one embodiment made from 0.014″diameter wire is about 0.059″, compared to a diameter of about 0.020″for eyes elsewhere in the graft.

Although the pivot points (apexes 213, 214) in the illustratedembodiment are on the medial plane, they may be moved laterally such as,for example, to the axis of each of the iliac branches. In thisvariation, each iliac branch will have an anterior and a posterior pivotlink on or about its longitudinal axis, for a total of four unique pivotlinks at the bifurcation. Alternatively, the pivot points can be movedas far as to lateral apexes 211 and 216. Other variations will beapparent to those of skill in the art in view of the disclosure herein.

To facilitate lateral rotation of the iliac branches 202, 204 about thepivot points and away from the longitudinal axis of the aorta trunkportion 200 of the graft, the remaining links between the aorta trunkportion 200 and the iliac branches 202, 204 preferably permit axialcompression and expansion. In general, at least one and preferablyseveral links lateral to the pivot point in the illustrated embodimentpermit axial compression or shortening of the graft to accommodatelateral pivoting of the iliac branch. If the pivot point is movedlaterally from the longitudinal axis of the aorta portion of the graft,any links medial of the pivot point preferably permit axial elongationto accommodate lateral rotation of the branch. In this manner, thedesired range of rotation of the iliac branches may be accomplished withminimal deformation of the wire, and with patency of the graft optimizedthroughout the angular range of motion.

To permit axial compression substantially without deformation of thewire, the lateral linkages, 211 and 212 for the right iliac, and 215 and216 for the left iliac, may be different from the previously describedapex-to-apex linkage configurations. The lateral linkages are preferablyslideable linkages, wherein a loop formed at the distal end of the iliacapex slidably engages a strut of the corresponding aortic truck portion.The loop and strut orientation may be reversed, as will be apparent tothose of skill in the art. Interlocking “elbows” without any distinctloop may also be used. Such an axially compressible linkage on thelateral margins of the assembled wire support structure allow the iliacbranch portions much greater lateral flexibility, thereby facilitatingplacement in patients who often exhibit a variety of iliac branchasymmetries and different angles of divergence from the aortic trunk.

Referring to FIG. 7, there is illustrated a plan view of a single formedwire used for rolling about a longitudinal axis to produce a foursegment straight tubular wire support for an iliac limb. The formed wireexhibits distinct segments, each corresponding to an individual tubularsegment in the tubular supports 202 or 204 (See FIG. 5). The distalsegment I, is adapted to articulate with the aortic trunk portion 200and the adjacent iliac limb portion. The distal segment (I) has twoapexes (e.g. corresponding to 211 and 212 on the right iliac portion 202in FIG. 5) which form a loop adapted to slidably engage a strut in thelateral wall of the aortic portion. These articulating loops (A) areenlarged in FIG. 8A. As discussed above, the loops are preferably loopedaround a strut on the corresponding apex of the proximal aortic segmentto provide a sliding linkage.

The apex 218 is proximally displaced relative to the other four apexesin the distal segment (I). Apex 218 (R or L) is designed to link withthe complementary 218 apex on the other iliac branch portion (See FIG.6). The apex 218 in the illustrated embodiment is formed adjacent ornear an intersegment connector 66, which extends proximally from thedistal segment.

The other apexes on the distal segment (I) of an iliac limb are designedto link with a loop on the corresponding apex of the proximal aorticsegment. Because many variations of this linkage are consistent with thepresent invention the form of the corresponding apexes may vary. In apreferred variation, the apexes (B) form a narrow Ushape, having aninside diameter of about 0.019 inches in an embodiment made from 0.012inch Conichrome wire (tensile strength 300 ksi minimum) as illustratedin FIG. 8B. The U-shaped, elongated axial portion of the apex shown inFIG. 8B permits the apex to be wrapped through and around acorresponding loop apex of the proximal aortic segment.

In more general terms, the wire support illustrated in FIGS. 5 and 6comprises a main body support structure formed from one or more lengthsof wire and having a proximal end, a distal end and a central lumenextending along a longitudinal axis. The wire support also comprises afirst branch support structure formed from one or more lengths of wireand having a proximal end, a distal end and a central lumentherethrough. The first branch support structure is pivotably connectedto the proximal end of the main body support structure. The tubular wiresupport further comprises a second branch support structure formed fromone or more lengths of wire and having a proximal end, a distal end anda central lumen extending therethrough. The distal end of the secondbranch support structure is pivotably connected to the proximal end ofthe main body support structure.

Further, the distal ends of the first and second branch structures maybe joined together by a flexible linkage, formed for example betweenapexes 218(R) and 218(L) in FIG. 5. By incorporating a medial linkagebetween the two branch support structures and pivotable linkages withthe main trunk, the first and second branch support structures can hingelaterally outward from the longitudinal axis without compromising thevolume of the lumen. Thus, the branches may enjoy a wide range oflateral movement, thereby accommodating a variety of patient and vesselheterogeneity. Additional corresponding apexes between the main trunkand each iliac branch may also be connected, or may be free floatingwithin the outer polymeric sleeve. Axially compressible laterallinkages, discussed above and illustrated in FIG. 6, may optionally beadded.

The proximal apexes (C) of the iliac limb portions are adapted to linkwith the distal apexes of the next segment. These proximal apexespreferably form loops, such as those illustrated in FIG. 8C, wherein theelongated axial portions of the corresponding proximal apex in theadjacent segment can wrap around the loop, thereby providing flexibilityof the graft.

The wire may be made from any of a variety of different alloys and wirediameters or non-round cross-sections, as has been discussed. In oneembodiment of the bifurcation graft, the wire gauge remainssubstantially constant throughout section A of the primary component 49and steps down to a second, smaller cross-section throughout section Bof primary component 108.

A wire diameter of approximately 0.018 inches may be useful in the aortatrunk portion of a graft having five segments each having 2.0 cm lengthper segment, each segment having six struts intended for use in theaorta, while a smaller diameter such as 0.012 inches might be useful forsegments of the graft having 6 struts per segment intended for the iliacartery.

In one embodiment of the present invention, the wire diameter may betapered throughout from the proximal to distal ends of the section Aand/or section B portions of the primary component 108. Alternatively,the wire diameter may be tapered incremental or stepped down, or steppedup, depending on the radial strength requirements of each particularclinical application. In one embodiment, intended for the abdominalaortic artery, the wire has a cross-section of about 0.018 inches in theproximal zone 110 and the wire tapers down regularly or in one or moresteps to a diameter of about 0.012 inches in the distal zone 112 of thegraft 102. End point dimensions and rates of taper can be varied widely,within the spirit of the present invention, depending upon the desiredclinical performance.

In general, in the tapered or stepped wire embodiments, the diameter ofthe wire in the iliac branches is no more than about 80% of the diameterof the wire in the aortic trunk. This permits increased flexibility ofthe graft in the region of the iliac branches, which has been determinedby the present inventors to be clinically desirable.

The collapsed prosthesis in accordance with the present invention has adiameter in the range of about 2 mm to about 10 mm. Preferably, themaximum diameter of the collapsed prosthesis is in the range of about 3mm to 6 mm (12 to 18 French). Some embodiments of the delivery catheterincluding the prosthesis will be in the range of from 18 to 20 or 21French; other embodiments will be as low as 19 F, 16 F, 14 F, orsmaller. After deployment, the expanded endoluminal vascular prosthesishas radially selfexpanded to a diameter anywhere in the range of about20 to 40 mm, corresponding to expansion ratios of about 1:2 to 1:20. Ina preferred embodiment, the expansion ratios range from about 1:4 to1:8, more preferably from about 1:4 to 1:6.

The self expandable bifurcation graft of the present invention can bedeployed at a treatment site in accordance with any of a variety oftechniques as will be apparent to those of skill in the art. One suchtechnique is disclosed in copending patent application Ser. No.08/802,478 entitled Bifurcated Vascular Graft and Method and Apparatusfor Deploying Same, filed Feb. 20, 1997, the disclosure of which isincorporated in its entirety herein by reference.

A partial cross-sectional side elevational view of one deploymentapparatus 120 in accordance with the present invention is shown in FIG.9. The deployment apparatus 120 comprises an elongate flexiblemulticomponent tubular body 122 having a proximal end 124 and a distalend 126. The tubular body 122 and other components of this system can bemanufactured in accordance with any of a variety of techniques wellknown in the catheter manufacturing field. Suitable materials anddimensions can be readily selected taking into account the naturalanatomical dimensions in the iliacs and aorta, together with thedimensions of the desired percutaneous access site.

The elongate flexible tubular body 122 comprises an outer sheath 128which is axially movably positioned upon an intermediate tube 130. Acentral tubular core 132 is axially movably positioned within theintermediate tube 130. In one embodiment, the outer tubular sheathcomprises extruded PTFE, having an outside diameter of about 0.250″ andan inside diameter of about 0.230″. The tubular sheath 128 is providedat its proximal end with a manifold 134, having a hemostatic valve 136thereon and access ports such as for the infusion of drugs or contrastmedia as will be understood by those of skill in the art.

The outer tubular sheath 128 has an axial length within the range offrom about 40″ to about 55″, and, in one embodiment of the deploymentdevice 120 having an overall length of 110 cm, the axial length of theouter tubular sheath 128 is about 52 cm and the outside diameter is nomore than about 0.250″. Thus, the distal end 129 of the tubular sheath128 is located at least about 16 cm proximally of the distal end 126 ofthe deployment catheter 120 in stent loaded configuration.

A distal segment of the deployment catheter 120 comprises an outertubular housing or cap 138, which terminates distally in an elongateflexible tapered distal tip 140. The distal housing 138 and tip 140 areaxially immovably connected to the central core 132 at a connection 142.

In a preferred embodiment of the present invention, the central tubularcore 132 is axially movably positioned within but rotationally locked tothe intermediate tube 130. The intermediate tube 130 is preferably alsoaxially movably positioned within but rotationally locked to the outersheath 128. In this manner, the rotational orientation of the centraltubular core 132 remains fixed with respect to the rotationalorientation of the outer sheath 128.

Rotational engagement can be accomplished in any of a variety of ways,normally involving complementary surface structures such as keys orsplines on the associated components. For example, the central tubularcore 132 can be provided with a radially outwardly extending projection,along a portion or all of its axial length. This projection is slidablyreceived within a radially outwardly extending slot on the interiorsurface of the intermediate tube 130, or component secured thereto.Alternatively, a radially inwardly extending projection on intermediatetube 130 or associated component can be received with an axiallyextending recess on the outer surface of the central tubular core 132.Alternatively, any of a variety of non-round configurations for thecentral tubular core 132 such as elliptical, oval, triangular, square,polygonal, and the like, can be slidably received within acomplementary-shaped aperture on or connected to the intermediate tube130.

In the illustrated embodiment, the cross section of the central tubularcore 132 deviates from circular by the provision of one or two opposingflat sides extending axially along its length. A corresponding apertureis provided in a rotational lock 125 provided at the proximal end of theintermediate tube 130. See FIG. 9. Thus, rotation of the intermediatetube 130 will cause a similar rotation of the central tubular core 132.

Similarly, the intermediate tube 130 is provided with one or twoopposing flat surfaces to be slidably received through a complementaryaperture in a rotational lock 133 on manifold 134. See FIG. 9. Theresulting assembly enables rotation of the manifold 134 to cause acommensurate rotation of the intermediate tube 130 and central tubularcore 132. Specific dimensions and design details of the rotational lockdisclosed herein will be readily apparent to those of skill in the artin view of the disclosure herein.

As can be seen from FIG. 10, a junction 131 is formed between the distalend 129 of outer sheath 128 and outer tubular housing 138. Proximalretraction of the outer sheath 128 with respect to the intermediate tube130 and outer tubular housing 138 will expose the compressed iliacbranches of the graft, as will be discussed in more detail below.

The distal tip 140 preferably tapers from an outside diameter of about0.225″ at its proximal end to an outside diameter of about 0.070″ at thedistal end thereof. The overall length of the distal tip 140 in oneembodiment of the deployment catheter 120 is about 3″. However, thelength and rate of taper of the distal tip 140 can be varied dependingupon the desired trackability and flexibility characteristics. Thedistal end of the housing 138 is secured to the proximal end of thedistal tip 140 such as by thermal bonding, adhesive bonding, and/or anyof a variety of other securing techniques known in the art. The proximalend of distal tip 140 is preferably also directly or indirectlyconnected to the central core 132 such as by a friction fit and/oradhesive bonding.

In at least the distal section of the catheter, the central core 132preferably comprises a length of hypodermic needle tubing 134. Thehypodermic needle 134 tubing may extend throughout the length of thecatheter to the proximal end thereof, or may be secured to the distalend of a proximal extrusion as illustrated for example in FIG. 6. Acentral guidewire lumen 144 extends throughout the length of the tubularcentral core 132, having a distal exit port 146 and a proximal accessport 148 as will be understood by those of skill in the art.

Referring to FIGS. 10-12, a bifurcated endoluminal graft 150 isillustrated in a compressed configuration within the deployment catheter120. The graft 150 comprises a distal aortic section 152, a proximalipsilateral iliac portion 154, and a proximal contralateral iliacportion 156. The aortic trunk portion 152 of the graft 150 is containedwithin the tubular housing 138. Distal axial advancement of the centraltubular core 132 will cause the distal tip 140 and housing 138 toadvance distally with respect to the graft 150, thereby permitting theaortic trunk portion 152 of the graft 150 to expand to its larger,unconstrained diameter. Distal travel of the graft 150 is prevented by adistal stop 158 which is axially immovably connected to the intermediatetube 130. Distal stop 158 may comprise any of a variety of structures,such as an annular flange or component which is adhered to, bonded to orintegrally formed with a tubular extension 160 of the intermediate tube132. Tubular extension 160 is axially movably positioned over thehypotube central core 132.

The tubular extension 160 extends axially throughout the length of thegraft 150. At the proximal end of the graft 150, a step 159 axiallyimmovably connects the tubular extension 160 to the intermediate tube130. In addition, the step 159 provides a proximal stop surface toprevent proximal travel of the graft 150 on the catheter 120. Thefunction of step 159 can be accomplished through any of a variety ofstructures as will be apparent to those of skill in the art in view ofthe disclosure herein. For example, the step 159 may comprise an annularring or spacer which receives the tubular extension 160 at a centralaperture therethrough, and fits within the distal end of theintermediate tube 130. Alternatively, the intermediate tube 130 can bereduced in diameter through a generally conical section or shoulder tothe diameter of tubular extension 160.

Proximal retraction of the outer sheath 128 will release the iliacbranches 154 and 156 of the graft 150. The iliac branches 154 and 156will remain compressed, within a first (ipsilateral) tubular sheath 162and a second (contralateral) tubular sheath 164. The first tubularsheath 162 is configured to restrain the ipsilateral branch of the graft150 in the constrained configuration, for implantation at the treatmentsite. The first tubular sheath 162 is adapted to be axially proximallyremoved from the iliac branch, thereby permitting the branch to expandto its implanted configuration. In one embodiment, the first tubularsheath 162 comprises a thin walled PTFE extrusion having an outsidediameter of about 0.215″ and an axial length of about 7.5 cm. A proximalend of the tubular sheath 162 is necked down such as by heat shrinkingto secure the first tubular sheath 162 to the tubular extension 160. Inthis manner, proximal withdrawal of the intermediate tube 130 will inturn proximally advance the first tubular sheath 162 relative to thegraft 150, thereby deploying the self expandable iliac branch of thegraft 150.

The second tubular sheath 164 is secured to the contralateral guidewire166, which extends outside of the tubular body 122 at a point 168, suchas may be conveniently provided at the junction 131 between the outertubular sheath 128 and the distal housing 138. The second tubular sheath164 is adapted to restrain the contralateral branch of the graft 150 inthe reduced profile. In one embodiment of the invention, the secondtubular sheath 164 has an outside diameter of about 0.215″ and an axiallength of about 7.5 cm. The second tubular sheath 164 can have asignificantly smaller cross-section than the first tubular sheath 162,due to the presence of the tubular core 132 and intermediate tube 130within the first iliac branch 154.

The second tubular sheath 164 is secured at its proximal end to a distalend of the contralateral guidewire 166. This may be accomplished throughany of a variety of securing techniques, such as heat shrinking,adhesives, mechanical interfit and the like. In one embodiment, theguidewire is provided with a knot or other diameter enlarging structureto provide an interference fit with the proximal end of the secondtubular sheath 156, and the proximal end of the second tubular sheath156 is heat shrunk and/or bonded in the area of the knot to provide asecure connection. Any of a variety of other techniques for providing asecure connection between the contralateral guidewire 166 and tubularsheath 156 can readily be used in the context of the present inventionas will be apparent to those of skill in the art in view of thedisclosure herein. The contralateral guidewire 166 can comprise any of avariety of structures, including polymeric monofilament materials,braided or woven materials, metal ribbon or wire, or conventionalguidewires as are well known in the art.

Referring to FIGS. 13 and 14, there is illustrated a fragmentary sideelevational view of an enhanced flexibility embodiment of the deploymentcatheter of the present invention. In this embodiment, the distalhypotube 134 component of the central tubular core 132 comprises aflexible wall such as a braided polyimide tubing. In one embodiment, thepolyimide tubing has an inside diameter of about 0.059″ and an outsidediameter of about 0.071″. An internal braid is made from 0.00 15″stainless steel 304 wire at a pic count of about 50 braids per inch,such as may be obtained from Phelps Dodge (GA) or H. V. Technologies(GA). The use of flexible tubing such as spiral cut layers or woven orbraided tubing in place of conventional stainless steel or other metalhypotubing increases the lateral flexibility of the assembled device,which facilitates the placement and deployment steps.

However, introduction of a flexible hypotube 135 creates a flex point inthe catheter at about the junction 131 between the distal end 129 ofouter sheath 128 and the proximal end of the outer tubular housing 138.To prevent kinking at the junction 131, a reinforcement structure 161 ispreferably provided within the catheter, spanning the junction 131. Inthe illustrated embodiment, the reinforcement structure 161 is carriedby the tubular extension 160 of intermediate tube 130. The reinforcementstructure 161 is in the form of a tubular element such as a stainlesssteel hypotube. The hypotube preferably has a length within the range offrom about 40 mm to about 60 mm, a wall thickness within the range offrom about 0.002″ to about 0.003″ and is secured immovably to thetubular extension 160. Any of a variety of other reinforcementstructures 161 can also be used, such as spiral cut or woven or braidedlayers, polymeric tubing and the like, depending upon the desiredperformance characteristics. By positioning the reinforcement structure161 at about the axial location of the junction 131, the flexibilitycharacteristics of the catheter can be optimized, while permitting ahighly flexible hypotube 135.

The braided polyimide hypotube 135, or other braided or woven reinforcedtubular element can be secured to the enlarged diameter proximalcomponent of tubular core 132 (see FIG. 14) in any of a variety of ways.In the illustrated embodiment, a threaded insert 163 is adhesivelybonded to the polyimide hypotube component 135 of the tubular core 132using a flexible epoxy such as 310 T manufactured by Epotech (MASS.) orother adhesives known in the art.

In use, the free end of the contralateral guidewire 166 ispercutaneously inserted into the arterial system, such as at a firstpuncture in a femoral artery. The contralateral guidewire is advancedthrough the corresponding iliac towards the aorta, and crossed over intothe contralateral iliac in accordance with cross over techniques whichare well known in the art. The contralateral guidewire is then advanceddistally down the contralateral iliac where it exits the body at asecond percutaneous puncture site.

The deployment catheter 120 is thereafter percutaneously inserted intothe first puncture, and advanced along a guidewire (e.g. 0.035 inch)through the ipsilateral iliac and into the aorta. As the deploymentcatheter 120 is transluminally advanced, slack produced in thecontralateral guidewire 166 is taken up by proximally withdrawing theguidewire 166 from the second percutaneous access site. In this manner,the deployment catheter 120 is positioned in the manner generallyillustrated in FIG. 15. Referring to FIG. 16, the outer sheath 128 isproximally withdrawn while maintaining the axial position of the overalldeployment catheter 120, thereby releasing the first and second iliacbranches of the graft 150. Proximal advancement of the deploymentcatheter 120 and contralateral guidewire 166 can then be accomplished,to position the iliac branches of the graft 150 within the iliacarteries as illustrated.

Referring to FIG. 17, the central core 132 is distally advanced therebydistally advancing the distal housing 138 as has been discussed. Thisexposes the aortic trunk of the graft 150, which deploys into its fullyexpanded configuration within the aorta. As illustrated in FIG. 18, thecontralateral guidewire 166 is thereafter proximally withdrawn, therebyby proximally withdrawing the second sheath 164 from the contralateraliliac branch 156 of the graft 150. The contralateral branch 156 of thegraft 150 thereafter self expands to fit within the iliac artery. Theguidewire 166 and sheath 164 may thereafter be proximally withdrawn andremoved from the patient, by way of the second percutaneous access site.

Thereafter, the deployment catheter 120 may be proximally withdrawn torelease the ipsilateral branch 154 of the graft 150 from the firsttubular sheath 162 as shown in FIG. 19. Following deployment of theipsilateral branch 154 of the prosthesis 150, a central lumen throughthe aortic trunk 152 and ipsilateral branch 154 is sufficiently large topermit proximal retraction of the deployment catheter 120 through thedeployed bifurcated graft 150. The deployment catheter 120 maythereafter be proximally withdrawn from the patient by way of the firstpercutaneous access site.

While a number of preferred embodiments of the invention and variationsthereof have been described in detail, other modifications and methodsof using and medical applications for the same will be apparent to thoseof skill in the art. Accordingly, it should be understood that variousapplications, modifications, and substitutions may be made ofequivalents without departing from the spirit of the invention or thescope of the claims.

What is claimed is:
 1. An endoluminal graft deployment catheter,comprising: a proximal outer tube section, having a proximal end and adistal end; an intermediate tube extending through the proximal tubesection and beyond the distal end; a central core, extending through theintermediate tube; and a cap attached to the central core; wherein theintermediate tube comprises at least a first surface that cooperateswith at least a second surface of the central core to inhibit relativerotation between the intermediate tube and the central core and thecentral core is axially moveable between a first position and a secondposition within the intermediate tube.
 2. An endoluminal graftdeployment catheter as in claim 1, wherein the intermediate tube isrotationally linked to the outer tube.
 3. An endoluminal graftdeployment catheter as in claim 1, wherein the cap is axially movablebetween a first position in which it contacts the outer tube and asecond position in which it is spaced distally apart from the outertube.
 4. An endoluminal graft deployment catheter as in claim 3, whereinthe central core comprises a flexible tube.
 5. An endoluminal graftdeployment catheter as in claim 4, wherein the flexible tube comprises apolymeric braid.
 6. An endoluminal graft deployment catheter as in claim5, wherein the flexible tube further comprises a reinforcing elementwhich spans the point of contact between the cap and the outer tube. 7.An endoluminal graft deployment catheter as in claim 6, wherein thereinforcing element comprises a tubular element carried by the flexibletube.
 8. An endoluminal graft deployment catheter, comprising: anelongate flexible body, having a proximal end and a distal end; aproximal outer tube section, having a proximal end and a distal end; adistal outer tube section, having a proximal end and a distal end, theproximal outer tube section being rotationally linked within theelongate flexible body to the distal outer tube section; and a centralcore, extending through the proximal and distal outer tube sections;wherein the proximal and distal outer tube sections define a prosthesiscavity therein for carrying a prosthesis; and axial separation of theproximal outer tube section from the distal outer tube section opens thecavity to release the prosthesis.
 9. An endoluminal graft deploymentcatheter as in claim 8, where in each of the proximal outer tube sectionand the distal outer tube section is rotationally linked to the centralcore.
 10. An endoluminal graft deployment catheter as in claim 8,wherein at least one of the proximal outer tube section and the distalouter tube section is axially movable between a first position in whichthe cavity is closed and a second position in which the cavity is open.11. An endoluminal graft deployment catheter as in claim 10, comprisinga junction between the proximal outer tube section and the distal outertube section when the cavity is closed, and further comprising areinforcing element spanning the junction.
 12. An endoluminal graftdeployment catheter as in claim 11, wherein the reinforcing elementcomprises a tube.
 13. An endoluminal graft deployment catheter as inclaim 8, wherein each the proximal outer tube section and the distalouter tube section is rotationally linked to the central core within theelongate flexible body.
 14. An endoluminal graft deployment catheter,comprising: an elongate, flexible body, having a proximal end and adistal end; a proximal outer tube section having a proximal end and adistal end; a distal outer tube section, having a proximal end and adistal end; a central core, extending between the proximal outer tubesection and the distal outer tube section, wherein at least one of theproximal outer tube section and the distal outer tube section is axiallymoveable between a first position in which the proximal outer tubesection and the distal outer tube section are adjacent each other anddefine at least in part a prosthesis cavity for carrying a prosthesis,and a second position in which the proximal outer tube section and thedistal outer tube section are spaced apart, the proximal outer tubesection and the distal outer tube section forming a junction when in thefirst position; and a reinforcing element carried by the catheter withinthe prosthesis and spanning the junction.
 15. An endoluminal graftdeployment catheter as in claim 14, wherein the reinforcing elementcomprises a tube.
 16. An endoluminal graft deployment catheter,comprising: a proximal outer tube section, having a proximal end and adistal end; an intermediate tube extending through the proximal tubesection and beyond the distal end; a central core, extending through theintermediate tube; and a cap attached to the central core; wherein thecentral core is rotationally linked within the catheter to theintermediate tube and the central core is axially moveable between afirst position and a second position within the intermediate tube. 17.An endoluminal graft deployment catheter as in claim 16, wherein theintermediate tube is rotationally linked within the catheter to theouter tube.
 18. An endoluminal graft deployment catheter as in claim 16,wherein the cap is axially movable between a first position in which itcontacts the outer tube and a second position in which it is spaceddistally apart from the outer tube.
 19. An endoluminal graft deploymentcatheter as in claim 18, wherein the central core comprises a flexibletube.
 20. An endoluminal graft deployment catheter as in claim 19,wherein the flexible tube comprises a polymeric braid.
 21. Anendoluminal graft deployment catheter as in claim 20, wherein theflexible tube further comprises a reinforcing element which spans thepoint of contact between the cap and the outer tube.
 22. An endoluminalgraft deployment catheter, comprising: an elongate flexible body, havinga proximal end and a distal end; a proximal outer tube section, having aproximal end and a distal end; a distal outer tube section, having aproximal end and a distal end, the proximal outer tube section beingrotationally linked within the elongate flexible body to the distalouter tube section; and a central core, extending through the proximaland distal outer tube sections; wherein the proximal and distal outertube sections define a prosthesis cavity therein for carrying aprosthesis; and axial separation of the proximal outer tube section fromthe distal outer tube section opens the cavity to release theprosthesis; at least one of the proximal outer tube section and thedistal outer tube section is axially movable between a first position inwhich the cavity is closed and a second position in which the cavity isopen; and the catheter further comprising a junction between theproximal outer tube section and the distal outer tube section when thecavity is closed and a reinforcing element spanning the junction.
 23. Anendoluminal graft deployment catheter as in claim 22, wherein thereinforcing element comprises a tube.
 24. An endoluminal graftdeployment catheter as in claim 22, wherein the central core comprises aflexible tube.
 25. An endoluminal graft deployment catheter as in claim24, wherein the flexible tube comprises a polymeric braid.